#include <bits/stdc++.h>
using namespace std;

int main(void)
{
    unsigned long long x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;
    
    if( (((x1+2)==x2) && ((y1+2)==y2)) ||
        (((x1+2)==x2) && ((y1-2)==y2)) || 
        (((x1-2)==x2) && ((y1+2)==y2)) || 
        (((x1-2)==x2) && ((y1-2)==y2)))
        cout << "Yes" << endl;
    else
        cout << "No" << endl;

    return 0;
}